Valve assembly and method

ABSTRACT

Embodiments of the present disclosure present a valve assembly that includes a valve body having a gas passage bore, a valving bore extending along a longitudinal axis and intersecting the gas passage bore, a first bearing surface concentric with the longitudinal axis and a radially spaced apart second bearing surface concentric with the longitudinal axis, wherein an interface of the gas passage bore and the valving bore defines a flow port radially intermediate the first bearing surface and the second bearing surface. The valve assembly further includes a shaft valve extending along the longitudinal axis and rotatably mounted in the valving bore.

BACKGROUND Field of the Disclosure

The present disclosure relates to valves and particularly to flowcontrol including gas flow control and more particularly to butterflytype valves.

Description of Related Art

A valve is a device that is able to regulate or control the flow of agas, liquid and/or particulates by opening and closing a channel orpassageway. When a valve is in the open position, fluid is typicallyable to flow in a direction from high pressure to low pressure. When avalve is in the closed position, fluid flow is typically obstructed fromflowing.

SUMMARY OF THE DISCLOSURE

In view of the foregoing, it is an object of the present disclosure toprovide a method and apparatus.

A first exemplary embodiment of the present disclosure provides a valveassembly. The valve assembly includes a valve body having a gas passagebore, a valving bore extending along a longitudinal axis andintersecting the gas passage bore, a first annular bearing surfaceconcentric with the longitudinal axis and a radially spaced apart secondannular bearing surface concentric with the longitudinal axis, whereinan interface of the gas passage bore and the valving bore defines a flowport radially intermediate the first bearing surface and the secondbearing surface. The valve assembly further includes a shaft valveextending along the longitudinal axis and rotatably mounted in thevalving bore, the shaft valve having a first peripheral contact surfaceconfigured to engage the first bearing surface, a second peripheralcontact surface configured to engage the second bearing surface and avane radially intermediate the first peripheral contact surface and thesecond peripheral contact surface, wherein the first and the secondperipheral contact surfaces have a given diameter and the vaneencompasses the given diameter and wherein rotation of the shaft valverelative to the valve body selectively permits flow through the gaspassage bore.

A second exemplary embodiment of the present disclosure provides anexhaust gas recirculation valve. The exhaust gas recirculation valveincludes a valve body having a gas passage bore extending between atleast one inlet and an at least one outlet, wherein the at least oneinlet is configured to receive an exhaust gas from an exhaust manifoldof an internal combustion engine and the at least one outlet isconfigured to pass exhaust to an inlet manifold of the internalcombustion engine, the gas passage bore including a first inlet gaspassage extending from the at least one inlet, the valve body having avalving bore intersecting the first inlet gas passage, the valving boredefining a first circular bearing surface and a second annular bearingsurface. The exhaust gas recirculation valve further includes a shaftvalve slideably received within the valving bore, the shaft valve havinga first contact surface for rotatably engaging the first circularbearing surface and a second contact surface for rotatably engaging thesecond circular bearing surface, and a vane, wherein the first contactsurface, the second contact surface and the vane have a common diameter.

A third exemplary embodiment of the present disclosure provides amethod. The method includes providing a valve body having a gas passagebore, a valving bore extending along a longitudinal axis andintersecting the gas passage bore, a first annular bearing surfaceconcentric with the longitudinal axis and a radially spaced apart secondannular bearing surface concentric with the longitudinal axis, whereinan interface of the gas passage bore and the valving bore defines a flowport radially intermediate the first bearing surface and the secondbearing surface. The method further includes providing a shaft valveextending along the longitudinal axis and rotatably mounted in thevalving bore, the shaft valve having a first peripheral contact surfaceconfigured to engage the first bearing surface, a second peripheralcontact surface configured to engage the second bearing surface and avane radially intermediate the first peripheral contact surface and thesecond peripheral contact surface, wherein the first and the secondperipheral contact surfaces have a given diameter and the vaneencompasses the given diameter and wherein rotation of the shaft valverelative to the valve body selectively permits flow through the gaspassage bore.

A fourth exemplary embodiment of the present disclosure provides amethod. The method includes forming a valve body having a gas passagebore extending between at least one inlet and an at least one outlet,wherein the at least one inlet is configured to receive an exhaust gasfrom an exhaust manifold of an internal combustion engine and the atleast one outlet is configured to pass exhaust to an inlet manifold ofthe internal combustion engine, the gas passage bore including a firstinlet gas passage extending from the at least one inlet, the valve bodyhaving a valving bore intersecting the first inlet gas passage, thevalving bore defining a first circular bearing surface and a secondannular bearing surface. The method further includes forming a shaftvalve slideably received within the valving bore, the shaft valve havinga first contact surface for rotatably engaging the first circularbearing surface and a second contact surface for rotatably engaging thesecond circular bearing surface, and a vane, wherein the first contactsurface, the second contact surface and the vane have a common diameter.

The following will describe embodiments of the present disclosure, butit should be appreciated that the present disclosure is not limited tothe described embodiments and various modifications of the invention arepossible without departing from the basic principles. The scope of thepresent disclosure is therefore to be determined solely by the appendedclaims.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is an exterior view of an exemplary valve body and shaft valvesuitable for use in practicing exemplary embodiments of this disclosure.

FIG. 2 is a cross-sectional view of an exemplary valve body suitable foruse in practicing exemplary embodiments of this disclosure.

FIG. 3 is a perspective view of an exemplary shaft valve suitable foruse in practicing exemplary embodiments of this disclosure.

FIG. 4 is a cross-sectional view of an exemplary valve body and shaftvalve suitable for use in practicing exemplary embodiments of thisdisclosure.

FIG. 5 is another cross-sectional view of an exemplary valve body andshaft valve suitable for use in practicing exemplary embodiments of thisdisclosure.

FIG. 6 is yet another cross-sectional view of an exemplary valve bodyand shaft valve suitable for use in practicing exemplary embodiments ofthis disclosure.

FIG. 7 is a front cross-sectional view of an exemplary valve body andshaft valve suitable for use in practicing exemplary embodiments of thisdisclosure.

FIG. 8 is a side elevational view of a seal face suitable for use inpracticing exemplary embodiments of this disclosure.

FIG. 9 is a side elevational view of a shaped seal face suitable for usein practicing exemplary embodiments of this disclosure.

FIG. 10 is another front cross-sectional view of an exemplary valve bodyand shaft valve suitable for use in practicing exemplary embodiments ofthis disclosure.

FIG. 11 is a perspective cross-sectional view of an exemplary valve bodyand shaft valve suitable for use in practicing exemplary embodiments ofthis disclosure.

FIG. 12 is a graph illustrating flow rates through a gas passage vs.angular location of a shaft within the gas passage in accordance withexemplary embodiments of this disclosure.

FIG. 13 is another embodiment of an exemplary valve body and shaft valvesuitable for use in practicing exemplary embodiments of this disclosure.

FIG. 14 is another perspective cross-sectional view of an exemplaryvalve body and shaft valve suitable for use in practicing exemplaryembodiments of this disclosure.

FIG. 15 is a top view of the shape of the gas passage intersection withthe valving bore suitable for use in practicing exemplary embodiments ofthis disclosure.

FIG. 16 is another top view of the shape of the gas passage intersectionwith the valving bore suitable for use in practicing exemplaryembodiments of this disclosure.

FIG. 17 is an exemplary logic flow diagram in accordance with a methodfor practicing exemplary embodiments of this disclosure.

DETAILED DESCRIPTION OF THE DISCLOSURE

Embodiments of the present disclosure can be used in exhaust gasrecirculating valves (EGR) connected to exhaust manifolds 101 of acombustion engine 103 (shown in FIG. 1) to divert metered amounts of theexhaust gas to intake manifolds 105 for re-burn by the engine. Theexhaust gases are mixed with fresh air/fuel mixtures resulting in alowering of combustion temperature and a reduction in the formation ofharmful compounds such as nitrous oxide. Embodiments of the presentdisclosure provide a valve body and a single piece shaft valve having avane with butterfly plate flow geometry. The diameter of the singlepiece shaft valve is relatively uniform throughout its longitudinal axisincluding the vane portion of the shaft valve.

It is contemplated that embodiments of the present disclosure can beused in place of traditional butterfly valves. In this embodiment, thevalve will include a body having a relatively large-diameter first borethere through for passage of a gas, and a second relativelysmall-diameter bore transverse to the first bore for supporting arotatable shaft on which is mounted a valve plate (known in the art as a“butterfly”) for controllably occluding the first bore in response torotation of the shaft to control the flow of gas.

Embodiments of the valve of the present disclosure include a valve bodyand a shaft valve rotatably connected to the valve body.

Valve Body

Referring to FIGS. 1 and 2, shown is a valve body 102, which includes agas passage bore 104 extending between an inlet and an outlet. It iscontemplated in some configurations, the gas passage bore 104 willinclude a plurality of inlets or a plurality of outlets. As seen in FIG.2, the valve body 102 includes two gas inlet passages 106, 108 and acombined gas outlet passage 110. The two exhaust gas inlet passages 106,108 admit exhaust gases from an engine exhaust manifold 101. The exhaustgas outlet passage 110 directs a metered flow of the exhaust gasestoward an engine inlet manifold 105.

The gas passage bore 104 can have any of a variety of cross sectionalprofiles (e.g., circular, oval, rectangular, triangular, etc), whereinthe profile is constant or varies along a length of the bore.

The valve body 102 also includes a cylindrical valving bore 112extending along a longitudinal axis and intersecting the gas passagebore 104. As seen in FIG. 2, the valving bore 112 extends through bothinlet passages 106, 108 of the gas passage bore 104.

Each intersection of the valving bore 112 and the gas passage 104defines a corresponding flow path cross sectional area.

Thus, the gas passage bore 104 can have a circular, obround, oval,rectilinear or faceted periphery, either at the intersection with thevalving bore 112, as well as upstream or downstream of the valving bore112.

A common or overlapping portion of the gas passage bore 104 and thevalving bore 112 defines a sealing band 114, 116 on opposite sides ofthe valving bore 112, wherein the sealing bands 114, 116 extend parallelto the longitudinal axis. As the valving bore 112 has a circular crosssection, the sealing bands 114, 116 have a generally arcuate crosssection taken perpendicular to the longitudinal axis. Thus, the sealingbands 114, 116 have a circumferential dimension about the longitudinalaxis (shown in FIGS. 7, 10, 11 and 14). The sealing bands 114, 116extend about the periphery of the valving bore 112 as well as extendingparallel to the longitudinal axis. In the configuration having aplurality of inlet passages (shown in FIG. 2), each intersection of thegas inlet passage 106, 108 and the valving bore 112 includes a pair ofopposing sealing bands 114, 116.

As set forth below, the sealing bands 114, 116 can be defined byparallel edges 118, 120, each parallel to the longitudinal axis.Alternatively, the sealing bands 114, 116 can include cut outs or ashaped edge 122, 124 (shown in FIG. 11) so that flow can be permitted orprecluded (depending on the shaping) relative to an adjacent portion ofthe sealing band 114, 116. That is, the sealing band 114, 116 can havevarying circumferential dimension along the longitudinal axis. Forexample, one end of the sealing band 114, 116 may have a circumferentialdimension of 0.5 cm (or an arc of 3 degrees) and the other end of thesealing band may have a circumferential dimension of 0.25 cm (or an arcof 1.5 degrees). As set forth below, this shaping can provide forincreased low flow control of the valve. Additionally, the curvature ofsealing bands 114, 116 provide a larger flow area than gas bore passage104 allowing for increased flow over sealing bands 114, 116.

In conjunction with the shaping of the sealing band 114, 116, the valvebody 102 can include fluting or channels 126, 128 (shown in FIG. 11)that extend from the sealing band 114 along the gas passage 104. Thevalve body 102 can also include triangular or V-shaped channels 1402,1404 (shown in FIG. 14). In these embodiments, the terminal edge ofchannels 126, 128 or the terminal edge 1406, 1408 of V-shaped channels1402, 1404 are adjacent to the sealing bands 114, 116 and do notterminate at the same rotational location of the valve shaft 140.Rather, the terminal edge 1406, 1408 is also V-shaped such that itsealing bands 114, 116 terminate at different rotational locations ofthe valve shaft 140. A cross sectional top view of the valve body 104 atFIG. 15 illustrates the V-shaped channels 1402, 1404.

In another embodiment, the valve body 102 can have a substantially flatsurface 1502, 1504 adjacent the sealing bands 114, 116, and does notinclude channels 126, 128. This embodiment is shown in FIG. 16, whichdepicts another cross sectional top view of valve body 104.

The valving bore 112 also defines at least two or more bearing surfaces130, 132 (shown in FIG. 2). As part of the valving bore 112, the bearingsurfaces 130, 132 have the same diameter as the valving bore 112. Thebearing surfaces 130, 132 are interfacing surfaces for supportingrotation of the shaft valve 134 relative to the valve body 102. Thebearing surfaces 130, 132 are cylindrical in shape and have a diameterto provide for operable rotation of the shaft valve 134 relative to thevalve body 102.

Shaft Valve

The shaft valve 134 (shown in FIG. 3 and FIG. 4) is a cylindrical memberhaving a given diameter sized to be slideably received within thevalving bore 112 and rotatably retained within the valving bore 112.

The shaft valve 134 includes at least a first peripheral contact surface136 configured to engage the first bearing surface 130, a secondperipheral contact surface 138 configured to engage the second bearingsurface 132. As seen in the figures, the shaft valve 134 can include athird, or additional, peripheral contact surfaces for rotatably engagingcorresponding surfaces of the valve body 102.

The peripheral contact surfaces 136, 138 define a maximum diameter ofthe shaft valve 134. Except for the vanes 140, 142, it is contemplatedthat other peripheral sections of the shaft valve 134 can have aslightly reduced diameter to facilitate operably locating the shaftvalve 134 within the valving bore 112 and reduce rotating frictionbetween the shaft valve 134 and the valve body 102. However, excludingvanes 140, 142, it should be appreciated that embodiments of the shaftvalve 134 include shaft valve 134 having a relatively uniform diameterthroughout its longitudinal axis.

The sizing of the diameter of the shaft valve 134 to the valving bore112 (and hence bearing surfaces 130, 132) is selected in accordance withstandard engineering practices to permit the shaft valve 134 to be slidinto the valving bore 112 and permit rotation of the shaft valve 134relative to the valve body 102. The diameter of the shaft valve 134relative to the valving bore 112 is selected to permit rotation andaccommodate tolerances of normal manufacturing processes. It should beappreciated that the shaft valve 134 is sized to valving bore 112 suchthat except for gas allowed to flow over the sealing surfaces andperipheral contact surfaces 136, 138 when the shaft valve 134 is in theopen position allowing gas to flow through gas passage bore 104, gas issubstantially obstructed from flowing between the shaft valve 134 andvalving bore 112.

As seen in the figures, the shaft valve 134 can include a length ofreduced diameter to form a shank 144 for engaging a drive or controlmechanism for selectively imparting rotation of the shaft valve 134relative to the valve body 102. The shank 144 can include a facetedportion or a flat or flats, keyways or splines, or any other shape tocooperatively engage with the drive or control mechanism. The drive orcontrol mechanism can be any of a variety of configurations including anengine control module (ECM) and an electric, electromechanical orhydraulic motor.

The shaft valve 134 also includes a vane 142 longitudinally intermediatethe first peripheral contact surface 136 and the second peripheralcontact surface 138. As seen in the figures, the shaft valve 134 caninclude a number of vanes 140, 142 corresponding to the number of gaspassage bores 104.

The vanes 140, 142 are configured to selectively engage the sealingbands 114, 116 to preclude (maximally inhibit) flow through therespective gas passage 114, 116. That is, each edge of the vane 140, 142includes a seal face 146, 148, wherein the distance between the sealfaces 146, is the diameter of the shaft valve 134.

The vanes 140, 142 are generally defined by a pair of opposite recesses150, 152 in the shaft valve 134. Thus, by rotation of the shaft valve134 relative to the valve body 102, the vane 140 moves from a sealedorientation with each seal faces 146, 148 engaging a correspondingsealing band 114, 115 of the valve body 102 to a fully open positionparallel to the flow.

The sealing bands 114, 116 can have any of a variety of configurationsand dimensions. For example, by forming the sealing bands 114, 116 tohave a circumferential dimension that is greater, such as by 1.1, 1.4,1.6 or more times a dimension of the seal face 146, 148 of the vane 140,142.

The recesses 150, 152 forming the vane 140 can be configured to providethe vane 140 with a constant thickness across the diameter of the shaftvalve 134 or a varying thickness across the shaft valve 134. As seen inFIGS. 7, 10, and 14, the vane 140 has a first thickness encompassing thelongitudinal axis and a reduced or lesser thickness at the seal face146, 148.

Referring to FIGS. 7 and 10, the seal face 146, 148 is defined bygenerally parallel edges extending parallel to the longitudinal axis.That is, the seal face 146, 148 has a generally rectangular shape(though having a curvature corresponding to the cylindrical periphery ofthe shaft valve 134) (shown in FIGS. 8 and 9). However, as shown in thefigures, it is possible to shape the seal face 146, 148 so that the sealface 146, 148 has a varied circumferential dimension wherein flow wouldbe permitted along some of the vane 140 while remaining precluded from adifferent portion of the vane 140 as the vane 140 rotates relative tothe valve body 102.

Similarly, the sealing band 114, 115 and corresponding seal face 146,148 can be differently sized for a given vane 140. This further allowsfor customized flow control as for a predestined rotation of the shaftvalve 134, gas can flow about one edge of the vane 140, while theremaining edge of the vane 140 precludes flow. Embodiments include thevalve shaft 134 having a substantially flat sealing face 146, 148 asshown in FIG. 14. In the embodiment depicted in FIG. 14, vane 140includes steps 1410, which allow for vane 140 to be formed through lesscostly manufacturing means. In this embodiment the shaft width (i.e.,distance between sealing face 146 and sealing face 148 is slightlylarger than the distance between sealing bands 114, 116 in order tocreate a sealed interface between the sealing faces 146, 148 and thesealing bands 114, 115 to prevent a flow of gas through the passage whenthe shaft valve 134 is in the closed position.

By selecting the relative sizing of the sealing bands 114, 115 of thevalve body 102 and the seal face 146, 148 of the vane 140, the shaftvalve 134 can permit slight rotation of the vane 140 relative the valvebody 102 without permitting flow. That is, the sensitivity of the shaftvalve 134 to a zero or null position relative to the valve body 102 canbe reduced. Similarly, the sensitivity of the shaft valve 134 throughlow angle rotations relative to the valve body 102 can be reduced. Asseen in FIG. 11, approximately 5% of the flow can be controlled throughapproximately 50° of rotation. This is illustrated in the graph shown inFIG. 12, which depicts the overall percentage flow rate on the y-axisversus rotational degree of the shaft valve 134 on the x-axis.

The sizing of the sealing band 114, 115 and seal face 146, 148 providean overlapping interface that allows for the elimination of aconventional end stop point, as well as the elimination of valve shutoff point shift due to thermal expansion dimensional changes atoperating temperatures up to 720° C. Indeed, embodiments include theabsence of a mechanical or physical stop or obstruction within oradjacent to the sealing bands 114, 115 that prevent rotation of valveshaft 134. In other words, embodiments include valve shaft 134 beingoperable to rotate in multiple directions and to multiple degreesgreater than 360 degrees in either direction (e.g., clockwise orcounterclockwise).

Referring to the figures, the shaft valve 134 can be used to set amaximum flow rate of the system. That is, by sizing the vane 140 to havea longitudinal dimension that is, for example 90%, 80% or 50% of thedimension of the gas passage bore 104 along the longitudinal axis, theshaft valve 134 can define a maximum flow path for the system. Thisallows the valve body 102, and corresponding gas passage bore 104 to besized to accommodate a relatively large system requiring a relativelyhigh flow rate, wherein the longitudinal dimension of the vane 140matches the longitudinal dimension of the associated gas passage bore104. However, since the shaft valve 134 can be readily replaced bymerely sliding out a first shaft valve 135 having a vane 141 (shown inFIG. 6) and sliding in a second shaft valve 134, the second shaft valve134 can have a vane 140 defined by a smaller longitudinal dimension,thereby restricting the maximum available flow rate of the valve. Asshown in FIG. 6, the longitudinal dimension of vane 141 is coextensivewith the longitudinal dimension of gas passage bore 104. Conversely, asshown in FIG. 5, the longitudinal dimension of vane 140 is smaller thanthe longitudinal dimension of gas passage bore 104. This allows a singlesize valve body 102 to be used in multiple operating environments.

As the shaft valve 134 can be used to limit the effective crosssectional area of the gas passage bore 104, customization of the systemis achieved by merely exchanging shaft valves 134 of different vane 140configurations. As seen in the figures the longitudinal dimension of thevane 140 can be less than the longitudinal dimension of the gas passagebore 104 at the interface with the valving bore 112. Thus, the shaftvalve 134 effectively determines the available cross sectional flow areaand hence flow rate.

It should be appreciated that while embodiments of the present valveassembly include a valve body 102 having two gas inlet passages 106, 108and a single gas outlet passage 110 (shown in FIG. 2), embodiments ofvalve body 102 include a single gas inlet passage 106 and a single gasoutlet passage 110 (shown in FIG. 13). In this embodiment, shaft valve134 includes a single vane 140 configured to selectively engage thesealing bands 114, 115 to preclude flow through the gas passage 104.

The presented embodiments offer significant advantages. These advantagesinclude a reduced number of parts which lowers manufacturing costs aswell as reduces the necessary steps for assembly. Further, as set forthabove, as the shaft valve 134 can be replaced by merely sliding the oldshaft valve 134 out of the valve body 102 and sliding the new shaftvalve 134 into the valve body 102, both component cost and assembly costare reduced. Also, as the number of parts is reduced, the necessaryaccounting for accumulated tolerances is reduced, thereby increasingmanufacturing pass rates.

The ability of the present system to confront an area of the sealingband 114, 115 with an area of the seal face 146, 148, rather than linecontacts of the prior designs, the present system can reduce leakagefrom approximately 30 Kg-40 Kg/hr to less than 10 Kg/hr and in selectconfigurations less than 1 Kg/hr. This reduced leakage is believed to benecessary to meet more stringent emissions standards being adoptedglobally.

Because the contact surfaces of the shaft valve 134 have the samediameter as the vane 140, the load on the bearing surfaces is less thanin a traditional butterfly valve. In certain configurations, the bearingload is decreased by a factor of 4. As there is reduced bearing load,alternative (and cheaper) materials can be used for the valve body 102as well as the shaft valve 134. Thus, less exotic materials for thevalve body 102 and shaft valve 134 are required.

The shaped sealing band 114, 115 in conjunction with the channels 126,128 in the valve body 102 provides for the configuration of the port,such as the “V” shape shown in FIG. 11, which improves a shearing actionof accumulated combustion materials, such as soot and carbon. Theimproved shearing results from the seal face 146, 148 of the vane 140progressively coming into engagement with the sealing band 114, 115,rather than the entire seal face 146, 148 engaging the entire sealingband 114, 115 at one time. By progressively engaging, a lower torquecontrol motor or drive can be used. The lower torque motor is lesscostly and typically adds less weight to the vehicle in which thepresent valve is installed. It should be appreciate that while FIGS. 11,14, and 15 depict “V” shaped channels 126, 128, embodiments of channels126, 128 can be shaped to include rectangular (shown in FIG. 16),circular, oval (shown in FIG. 9 as sealing face 146) or multiple “V”shaped channels in order to allow for different types of flow ratecontrol through gas bore passage 104.

As set forth above, the shaped sealing band and/or seal face whichprovide for the port configuration options such as “V” or other shapeschange flow output versus angular rotation of the shaft valve 134. Thisallows customization of the valve output flow for improved sensitivityat lower opening angles of the valve improving valve response.Additionally, the “V” shaped channels 126, 128 not only allows for fineradjustments in the amount of flow through gas bore passage 104, butchannels 126, 128 allow for finer adjustments in the velocity of flowthrough gas bore passage 104. That is, rotation of valve shaft 134allowing flow through only channels 126, 128 will have a higher flowvelocity when compared to the flow velocity when the sealing face 146,148 is no longer in contact with any portion of the sealing band 114,115.

Also, the use of the shaft valve 134 provides flexibility to adjustmaximum flow output by adjusting the machine depth or width of therecesses or cut outs in the shaft valve 134 as well as the number of cutouts without changing the package size or port configuration in thevalve body 102.

Reference is now made to FIG. 17, which presents an exemplary method orprocess for providing embodiments of the present disclosure. The processbegins at block 1702, which states (a) providing valve body having a gaspassage bore, a valving bore extending along a longitudinal axis andintersecting the gas passage bore, a first bearing surface concentricwith the longitudinal axis and a radially spaced apart second bearingsurface concentric with the longitudinal axis, wherein an interface ofthe gas passage bore and the valving bore defines a flow port radiallyintermediate the first bearing surface and the second bearing surface;and (b) providing a shaft valve extending along the longitudinal axisand rotatably mounted in the valving bore, the shaft valve having afirst peripheral contact surface configured to engage the first bearingsurface, a second peripheral contact surface configured to engage thesecond bearing surface and a vane radially intermediate the firstperipheral contact surface and the second peripheral contact surface,wherein the first and the second peripheral contact surfaces have agiven diameter and the vane encompasses the given diameter and whereinrotation of the shaft valve relative to the valve body selectivelypermits flow through the gas passage bore. Following block 1702, block1704 indicates wherein the valve body defines a pair of opposing sealingbands extending parallel to the longitudinal axis, each sealing bandconfigured to engage a corresponding longitudinal edge of the vane.

Some of the other non-limiting embodiments include block 1706, whichspecifies wherein the sealing bands have one of (i) a V-shaped edgeadjacent a channel defined in the valve body operable to allow a flow topass therethrough, (ii) a rectangular shaped edge, and (iii) an ovalshaped edge. Next, block 1708 states wherein the first peripheralcontact surface configured to engage the first bearing surface and thesecond peripheral contact surface configured to engage the secondbearing surface are operable to contact accumulated combustion productsdisposed on an edge of the sealing bands. Block 1710 indicates whereinthe first peripheral contact surface configured to engage the firstbearing surface and wherein the shaft valve is operable to rotateunobstructed 360 degrees within the valving bore.

The invention has been described in detail with particular reference toa presently preferred embodiment, but it will be understood thatvariations and modifications can be effected within the spirit and scopeof the invention. The presently disclosed embodiments are thereforeconsidered in all respects to be illustrative and not restrictive. Thescope of the invention is indicated by the appended claims, and allchanges that come within the meaning and range of equivalents thereofare intended to be embraced therein.

1. A valve assembly comprising: (a) a valve body having a gas passagebore, a valving bore extending along a longitudinal axis andintersecting the gas passage bore, a first annular bearing surfaceconcentric with the longitudinal axis and a radially spaced apart secondannular bearing surface concentric with the longitudinal axis, whereinan interface of the gas passage bore and the valving bore defines a flowport radially intermediate the first bearing surface and the secondbearing surface; and (b) a shaft valve extending along the longitudinalaxis and rotatably mounted in the valving bore, the shaft valve having afirst peripheral contact surface configured to engage the first bearingsurface, a second peripheral contact surface configured to engage thesecond bearing surface and a vane radially intermediate the firstperipheral contact surface and the second peripheral contact surface,wherein the first and the second peripheral contact surfaces have agiven diameter and the vane encompasses the given diameter and whereinrotation of the shaft valve relative to the valve body selectivelypermits flow through the gas passage bore.
 2. The valve assembly ofclaim 1, wherein the vane is defined by opposing recesses in the shaftvalve.
 3. The valve assembly of claim 1, wherein the vane is defined byopposite major surfaces, and at least a portion of the major surfacesare non-parallel.
 4. The valve assembly of claim 1, wherein a thicknessof the vane varies along a radius extending from the longitudinal axis.5. The valve assembly of claim 1, wherein the vane has a cross sectionsubstantially perpendicular to the longitudinal axis definingnon-parallel major surfaces.
 6. The valve assembly of claim 1, whereinthe vane has a cross section substantially perpendicular to thelongitudinal axis defining a first thickness at a first radial locationalong the longitudinal axis and a different second thickness at a secondradial location along the longitudinal axis.
 7. The valve assembly ofclaim 1, wherein the valve body defines a pair of opposing sealing bandsextending parallel to the longitudinal axis, each sealing bandconfigured to engage a corresponding longitudinal edge of the vane. 8.The valve assembly of claim 7, wherein the sealing bands have one of (i)a V-shaped edge adjacent a channel defined in the valve body operable toallow a flow to pass therethrough, (ii) a rectangular shaped edge, and(iii) an oval shaped edge.
 9. The valve assembly of claim 7, wherein thefirst peripheral contact surface configured to engage the first bearingsurface and the second peripheral contact surface configured to engagethe second bearing surface are operable to contact accumulatedcombustion products disposed on an edge of the sealing bands.
 10. Thevalve assembly of claim 1, wherein the shaft valve is operable to rotateunobstructed 360 degrees within the valving bore.
 11. The valve assemblyof claim 7, wherein the sealing bands have a sealing diameter that isgreater than a length of the longitudinal edge of the vane, and whereinthe shaft valve and the valve body are operable to prevent a flow of gasbetween them when the longitudinal edge of the vane is in contact withthe sealings bands.
 12. The valve assembly of claim 1, wherein one ofthe valve body and vane has a shaped sealing surface that defines anopening cross sectional area that varies corresponding to an amount ofrotation of the shaft valve operable to adjust flow rates through thegas passage bore relative to an angular position of the shaft valve. 13.An exhaust gas recirculation valve comprising: (a) a valve body having agas passage bore extending between at least one inlet and an at leastone outlet, wherein the at least one inlet is configured to receive anexhaust gas from an exhaust manifold of an internal combustion engineand the at least one outlet is configured to pass exhaust to an inletmanifold of the internal combustion engine, the gas passage boreincluding a first inlet gas passage extending from the at least oneinlet, the valve body having a valving bore intersecting the first inletgas passage, the valving bore defining a first circular bearing surfaceand a second annular bearing surface; and (b) a shaft valve slideablyreceived within the valving bore, the shaft valve having a first contactsurface for rotatably engaging the first circular bearing surface and asecond contact surface for rotatably engaging the second circularbearing surface, and a vane, wherein the first contact surface, thesecond contact surface and the vane have a common diameter.
 14. Theexhaust gas recirculation valve according to claim 11, wherein the shaftvalve is operable to rotate unobstructed by the valve body 360 degreeswithin the valving bore.
 15. The exhaust gas recirculation valve ofclaim 11, wherein the vane is defined by opposing recesses in the shaftvalve.
 16. A method comprising: (a) providing valve body having a gaspassage bore, a valving bore extending along a longitudinal axis andintersecting the gas passage bore, a first bearing surface concentricwith the longitudinal axis and a radially spaced apart second bearingsurface concentric with the longitudinal axis, wherein an interface ofthe gas passage bore and the valving bore defines a flow port radiallyintermediate the first bearing surface and the second bearing surface;and (b) providing a shaft valve extending along the longitudinal axisand rotatably mounted in the valving bore, the shaft valve having afirst peripheral contact surface configured to engage the first bearingsurface, a second peripheral contact surface configured to engage thesecond bearing surface and a vane radially intermediate the firstperipheral contact surface and the second peripheral contact surface,wherein the first and the second peripheral contact surfaces have agiven diameter and the vane encompasses the given diameter and whereinrotation of the shaft valve relative to the valve body selectivelypermits flow through the gas passage bore.
 17. The method of claim 16,wherein the valve body defines a pair of opposing sealing bandsextending parallel to the longitudinal axis, each sealing bandconfigured to engage a corresponding longitudinal edge of the vane. 18.The method of claim 17, wherein the sealing bands have one of (i) aV-shaped edge adjacent a channel defined in the valve body operable toallow a flow to pass therethrough, (ii) a rectangular shaped edge, and(iii) an oval shaped edge.
 19. The method of claim 17, wherein the firstperipheral contact surface configured to engage the first bearingsurface and the second peripheral contact surface configured to engagethe second bearing surface are operable to contact accumulatedcombustion products disposed on an edge of the sealing bands.
 20. Themethod of claim 16, wherein the shaft valve is operable to rotateunobstructed 360 degrees within the valving bore.